The present invention generally relates to color image pickup devices, and more particularly to a color image pickup device which obtains a color multiplexed signal from a pickup tube provided with a color stripe filter and performs a color demodulation in a single tube color television camera, for example.
In a conventional single tube color television camera, a color multiplexed signal is obtained by performing a scan in a direction perpendicular to the longitudinal direction of stripes of a color stripe filter which comprises a repetition of green (G), cyan (C) and white (W or transparent) stripes.
However, because the scanning is performed in the direction perpendicular to the longitudinal direction of the stripes of the color stripe filter, color components obtained via the color stripe filter are multiplexed by a carrier of 4 MHz which is relatively high for one period of the color stripe filter (that is, for one group of the G, C and W stripes). Generally, noise is high in the high frequency range, and the degree of modulation of the image pickup tube is low in the high frequency range. As a result, the signal-to-noise ratio becomes poor. In addition, the image pickup tube cannot reproduce color stripes with a high fidelity, and there is a problem in that the color reproducibility is poor.
Furthermore, since the scanning is performed in the direction perpendicular to the longitudinal direction of the stripes of the color stripe filter, the color components obtained via the color stripe filter are multiplexed in the sequence corresponding to the scanning direction. For this reason, the frequency band of the luminance signal becomes limited to a narrow frequency band by the color multiplexed signal (carrier), and there is a problem in that it is impossible to obtain a satisfactory horizontal resolution.